Nonuniform Distribution of Reach-Related and Torque-Related Activity in Upper Arm Muscles and Neurons of Primary Motor Cortex

2006 ◽  
Vol 96 (6) ◽  
pp. 3220-3230 ◽  
Author(s):  
Isaac Kurtzer ◽  
Troy M. Herter ◽  
Stephen H. Scott
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Muscular Activity ◽  
Elbow Flexion ◽  
Bimodal Distribution ◽  
The Body ◽  
Related Activity ◽  
Upper Arm ◽  
Reaching Task ◽  
Arm Muscles

The present study examined the activity of primate shoulder and elbow muscles using a novel reaching task. We enforced similar patterns of center-out movement while the animals countered viscous loads at their shoulder, elbow, both joints, or neither joint. Accordingly, we could examine reach-related activity during the unloaded condition and torque-related activity by comparing activity across load conditions. During unloaded reaching the upper arm muscles exhibited a bimodal distribution of preferred hand direction. Maximal reach-related activity occurred with hand movements mostly toward or away from the body. Arm muscles also exhibited a bimodal distribution of their preferred torque direction. Maximal torque-related activity typically occurred with shoulder-extension/elbow-flexion torque or shoulder-flexion/elbow-extension torque. Similar biases in reach-related and torque-related activity could be reproduced by optimizing a global measure of muscle activity. These biases were also observed in the neural activity of primary motor cortex (M1). The parallels between M1 and muscular activity demonstrate another link between motor cortical processing and the motor periphery and may reflect an optimization process performed by the sensorimotor system.

Characterization of Torque-Related Activity in Primary Motor Cortex During a Multijoint Postural Task

2007 ◽  
Vol 97 (4) ◽  
pp. 2887-2899 ◽  
Author(s):  
Troy M. Herter ◽  
Isaac Kurtzer ◽  
D. William Cabel ◽  
Kirk A. Haunts ◽  
Stephen H. Scott
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Bimodal Distribution ◽  
Joint Torque ◽  
Neural Responses ◽  
Joint Activities ◽  
Baseline Activity ◽  
Arm Muscles ◽  
Postural Task

The present study examined neural activity in the shoulder/elbow region of primary motor cortex (M1) during a whole-limb postural task. By selectively imposing torques at the shoulder, elbow, or both joints we addressed how neurons represent changes in torque at a single joint, multiple joints, and their interrelation. We observed that similar proportions of neurons reflected changes in torque at the shoulder, elbow, and both joints and these neurons were highly intermingled across the cortical surface. Most torque-related neurons were reciprocally excited and inhibited (relative to their unloaded baseline activity) by opposing flexor and extensor torques at a single joint. Although coexcitation/coinhibition was occasionally observed at a single joint, it was rarely observed at both joints. A second analysis assessed the relationship between single-joint and multijoint activity. In contrast to our previous observations, we found that neither linear nor vector summation of single-joint activities could capture the breadth of neural responses to multijoint torques. Finally, we studied the neurons' directional tuning across all the torque conditions, i.e., in joint-torque space. Our population of M1 neurons exhibited a strong bimodal distribution of preferred-torque directions (PTDs) that was biased toward shoulder-extensor/elbow-flexor (whole-limb flexor) and shoulder-flexor/elbow-extensor (whole-limb extensor) torques. Notably, we recently observed a similar bimodal distribution of PTDs in a sample of proximal arm muscles. This observation illustrates the intimate relationship between M1 and the motor periphery.

Laterality of Movement-Related Activity Reflects Transformation of Coordinates in Ventral Premotor Cortex and Primary Motor Cortex of Monkeys

2007 ◽  
Vol 98 (4) ◽  
pp. 2008-2021 ◽  
Author(s):  
Kiyoshi Kurata
Keyword(s):  
Motor Cortex ◽  
Neuronal Activity ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Visuomotor Transformation ◽  
Related Activity ◽  
Reaching Task ◽  
Ventral Premotor Cortex ◽  
Cortical Motor ◽  
Target Locations

The ventral premotor cortex (PMv) and the primary motor cortex (MI) of monkeys participate in various sensorimotor integrations, such as the transformation of coordinates from visual to motor space, because the areas contain movement-related neuronal activity reflecting either visual or motor space. In addition to relationship to visual and motor space, laterality of the activity could indicate stages in the visuomotor transformation. Thus we examined laterality and relationship to visual and motor space of movement-related neuronal activity in the PMv and MI of monkeys performing a fast-reaching task with the left or right arm, toward targets with visual and motor coordinates that had been dissociated by shift prisms. We determined laterality of each activity quantitatively and classified it into four types: activity that consistently depended on target locations in either head-centered visual coordinates (V-type) or motor coordinates (M-type) and those that had either differential or nondifferential activity for both coordinates (B- and N-types). A majority of M-type neurons in the areas had preferences for reaching movements with the arm contralateral to the hemisphere where neuronal activity was recorded. In contrast, most of the V-type neurons were recorded in the PMv and exhibited less laterality than the M-type. The B- and N-types were recorded in the PMv and MI and exhibited intermediate properties between the V- and M-types when laterality and correlations to visual and motor space of them were jointly examined. These results suggest that the cortical motor areas contribute to the transformation of coordinates to generate final motor commands.

scholarly journals Independent representations of ipsilateral and contralateral limbs in primary motor cortex

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Ethan A Heming ◽  
Kevin P Cross ◽  
Tomohiko Takei ◽  
Douglas J Cook ◽  
Stephen H Scott
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Contralateral Side ◽  
The Body ◽  
Motor Output ◽  
Neural Responses ◽  
Related Activity ◽  
Contralateral Limb ◽  
Mechanical Loads ◽  
Contralateral Motor

Several lines of research demonstrate that primary motor cortex (M1) is principally involved in controlling the contralateral side of the body. However, M1 activity has been correlated with both contralateral and ipsilateral limb movements. Why does ipsilaterally-related activity not cause contralateral motor output? To address this question, we trained monkeys to counter mechanical loads applied to their right and left limbs. We found >50% of M1 neurons had load-related activity for both limbs. Contralateral loads evoked changes in activity ~10ms sooner than ipsilateral loads. We also found corresponding population activities were distinct, with contralateral activity residing in a subspace that was orthogonal to the ipsilateral activity. Thus, neural responses for the contralateral limb can be extracted without interference from the activity for the ipsilateral limb, and vice versa. Our results show that M1 activity unrelated to downstream motor targets can be segregated from activity related to the downstream motor output.

scholarly journals Reduced Interhemispheric Coherence in Cerebellar Kainic Acid-Induced Lateralized Dystonia

2020 ◽  
Vol 11 ◽  
Author(s):  
Elena Laura Georgescu Margarint ◽  
Ioana Antoaneta Georgescu ◽  
Carmen Denise Mihaela Zahiu ◽  
Stefan-Alexandru Tirlea ◽  
Alexandru Rǎzvan Şteopoaie ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Kainic Acid ◽  
Primary Motor Cortex ◽  
Low Frequency ◽  
Muscular Activity ◽  
Cerebellar Hemisphere ◽  
Interhemispheric Coherence ◽  
General Locomotor Activity ◽  
Complex Circuits ◽  
The Right

The execution of voluntary muscular activity is controlled by the primary motor cortex, together with the cerebellum and basal ganglia. The synchronization of neural activity in the intracortical network is crucial for the regulation of movements. In certain motor diseases, such as dystonia, this synchrony can be altered in any node of the cerebello-cortical network. Questions remain about how the cerebellum influences the motor cortex and interhemispheric communication. This research aims to study the interhemispheric cortical communication between the motor cortices during dystonia, a neurological movement syndrome consisting of sustained or repetitive involuntary muscle contractions. We pharmacologically induced lateralized dystonia to adult male albino mice by administering low doses of kainic acid on the left cerebellar hemisphere. Using electrocorticography and electromyography, we investigated the power spectral densities, cortico-muscular, and interhemispheric coherence between the right and left motor cortices, before and during dystonia, for five consecutive days. Mice displayed lateralized abnormal motor signs, a reduced general locomotor activity, and a high score of dystonia. The results showed a progressive interhemispheric coherence decrease in low-frequency bands (delta, theta, beta) during the first 3 days. The cortico-muscular coherence of the affected side had a significant increase in gamma bands on days 3 and 4. In conclusion, lateralized cerebellar dysfunction during dystonia was associated with a loss of connectivity in the motor cortices, suggesting a possible cortical compensation to the initial disturbances induced by cerebellar left hemisphere kainate activation by blocking the propagation of abnormal oscillations to the healthy hemisphere. However, the cerebellum is part of several overly complex circuits, therefore other mechanisms can still be involved in this phenomenon.

Functional Properties of Neurons in the Primate Tongue Primary Motor Cortex During Swallowing

1997 ◽  
Vol 78 (3) ◽  
pp. 1516-1530 ◽  
Author(s):  
Ruth E. Martin ◽  
Gregory M. Murray ◽  
Pentti Kemppainen ◽  
Yuji Masuda ◽  
Barry J. Sessle
Keyword(s):  
Motor Cortex ◽  
Functional Properties ◽  
Primary Motor Cortex ◽  
Motor Behavior ◽  
Critical Role ◽  
Electromyographic Activity ◽  
Related Activity ◽  
Tongue Protrusion ◽  
Significant Difference ◽  
Tongue Movements

Martin, Ruth E., Gregory M. Murray, Pentti Kemppainen, Yuji Masuda, and Barry J. Sessle. Functional properties of neurons in the primate tongue primary motor cortex during swallowing. J. Neurophysiol. 78: 1516–1530, 1997. Recent studies conducted in our laboratory have suggested that the tongue primary motor cortex (i.e., tongue-MI) plays a critical role in the control of voluntary tongue movements in the primate. However, the possible involvement of tongue-MI in semiautomatic tongue movements, such as those in swallowing, remains unkown. Therefore the present study was undertakein in attempts to address whether tongue-MI plays a role in the semiautomatic tongue movements produced during swallowing. Extracellular single neuron recordings were obtained from tongue-MI, defined by intracortical microstimulation (ICMS), in two awake monkeys as they performed three types of swallowing (swallowing of a juice reward after successful tongue task performance, nontask-related swallowing of a liquid bolus, and nontask-related swallowing of a solid bolus) as well as a trained tongue-protrusion task. Electromyographic activity was recorded simultaneously from various orofacial and laryngeal muscles. In addition, the afferent input to each tongue-MI neuron and ICMS-evoked motor output characteristics at each neuronal recording site were determined. Neurons were considered to show swallow and/or tongue-protrusion task-related activity if a statistically significant difference in firing rate was seen in association with these behaviors compared with that observed during a control pretrial period. Of a total of 80 neurons recorded along 40 microelectrode penetrations in the ICMS-defined tongue-MI, 69% showed significant alterations of activity in relation to the swallowing of a juice reward, whereas 66% exhibited significant modulations of firing in association with performance of the trained tongue-protrusion task. Moreover, 48% showed significant alterations of firing in relation to both swallowing and the tongue-protrusion task. These findings suggest that the region of cortex involved in swallowing includes MI and that tongue-MI may play a role in the regulation of semiautomatic tongue movement, in addition to trained motor behavior. Swallow-related tongue-MI neurons exhibited a variety of swallow-related activity patterns and were distributed throughout the ICMS-defined tongue-MI at sites where ICMS evoked a variety of types of tongue movements. These findings are consistent with the view that multiple efferent zones for the production of tongue movements are activated in swallowing. Many swallow-related tongue-MI neurons had an orofacial mechanoreceptive field, particularly on the tongue dorsum, supporting the view that afferent inputs may be involved in the regulation of the swallowing synergy.

scholarly journals Primary motor cortex neurons classified in a postural task predict muscle activation patterns in a reaching task

2016 ◽  
Vol 115 (4) ◽  
pp. 2021-2032 ◽  
Author(s):  
Ethan A. Heming ◽  
Timothy P. Lillicrap ◽  
Mohsen Omrani ◽  
Troy M. Herter ◽  
J. Andrew Pruszynski ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Muscle Activation ◽  
Primary Motor Cortex ◽  
Network Connectivity ◽  
Spatiotemporal Patterns ◽  
Neural Population ◽  
Activation Patterns ◽  
Reaching Task ◽  
Muscle Activation Patterns ◽  
Muscle Groups

Primary motor cortex (M1) activity correlates with many motor variables, making it difficult to demonstrate how it participates in motor control. We developed a two-stage process to separate the process of classifying the motor field of M1 neurons from the process of predicting the spatiotemporal patterns of its motor field during reaching. We tested our approach with a neural network model that controlled a two-joint arm to show the statistical relationship between network connectivity and neural activity across different motor tasks. In rhesus monkeys, M1 neurons classified by this method showed preferred reaching directions similar to their associated muscle groups. Importantly, the neural population signals predicted the spatiotemporal dynamics of their associated muscle groups, although a subgroup of atypical neurons reversed their directional preference, suggesting a selective role in antagonist control. These results highlight that M1 provides important details on the spatiotemporal patterns of muscle activity during motor skills such as reaching.

scholarly journals A behavioral paradigm for cortical control of a robotic arm by freely moving rats in a one-dimensional center-out reaching task

2021 ◽  
Author(s):  
Syed Muhammad Talha Zaidi ◽  
Samet Kocatürk ◽  
Tunçer Baykaş ◽  
Mehmet Kocatürk
Keyword(s):  
Motor Cortex ◽  
Task Difficulty ◽  
Primary Motor Cortex ◽  
Robotic Arm ◽  
Difficulty Level ◽  
One Dimensional ◽  
Reaching Task ◽  
Freely Moving Rats ◽  
Behavioral Paradigm ◽  
Freely Moving

AbstractObjectiveBrain-machine interfaces (BMIs) are promising candidates for restoring the lost motor system functions. Center-out reaching task is a commonly used BMI control paradigm in humans and monkeys and has not been available for rodents yet. In this work, our goal was to develop a behavioral paradigm which enables rats to control a neuroprosthesis in a center-out reaching task applied in one-dimensional space.ApproachThe experimental setup mainly consisted of a behavioral cage and a robotic workspace outside the cage. Two distant targets were located on the left and right sides of the central starting position of the robot endpoint. An online transform algorithm was used to convert the activity of a pair of recorded primary motor cortex units into two robotic actions. An increase in the activity of one of the units directed the robot endpoint toward left while an increase in the other moved it toward right. The task difficulty level which was proportional to the distance between the selected target and the initial position of the robot endpoint at the beginning of trials was increased gradually as the rat adapts with the transform.Main ResultsAll three rats involved in the study were capable of achieving randomly selected targets with at least 78% accuracy in the highest task difficulty level, in center-out reaching task. A total of 9 out of 16 pairs of units examined were eligible for training in center-out reaching task. Two out of three rats were capable of reversal learning where the mapping between the activity of the unit pairs and the robotic actions were reversed.SignificanceThe present behavioral paradigm enabled freely moving rats to control a robotic arm through primary motor cortex neurons in a one-dimensional center-out reaching task. It may offer a cost-effective alternative for the BMI studies requiring one-dimensional, bidirectional neuroprosthetic actions.

scholarly journals The Excitability of Ipsilateral Motor Evoked Potentials Is Not Task-specific and Spatially Distinct From the Contralateral Motor Hotspot

2022 ◽  
Author(s):  
Nelly Seusing ◽  
Sebastian Strauss ◽  
Robert Fleischmann ◽  
Christina Nafz ◽  
Sergiu Groppa ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Evoked Potentials ◽  
Primary Motor Cortex ◽  
Biceps Brachii ◽  
Motor Evoked Potentials ◽  
Elbow Flexion ◽  
Motor Pathways ◽  
Task Dependence ◽  
Flexion Extension ◽  
Voluntary Contractions

Abstract ObjectiveThe role of ipsilateral descending motor pathways in voluntary movement of humans is still a matter of debate. Few studies have examined the task dependent modulation of ipsilateral motor evoked potentials (iMEPs). Here, we determined the location of upper limb biceps brachii (BB) representation within the ipsilateral primary motor cortex. MethodsMR-navigated transcranial magnetic stimulation mapping of the dominant hemisphere was undertaken with twenty healthy participants who made tonic unilateral, bilateral homologous or bilateral antagonistic elbow flexion-extension voluntary contractions. Map center of gravity (CoG) and area for each BB were obtained. ResultsThe map CoG of the ipsilateral BB was located more anterior-laterally than those of the contralateral BB within the primary motor cortex. However different tasks had no effect on either the iMEP CoG location or the size. ConclusionOur data suggests that ipsilateral and contralateral MEP might originate in distinct adjacent neural populations in the primary motor cortex, independent of task dependence.

scholarly journals Efficacy of Repetitive Transcranial Magnetic Stimulation for Acute Central Post-stroke Pain: A Case Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Calogero Malfitano ◽  
Angela Rossetti ◽  
Stefano Scarano ◽  
Chiara Malloggi ◽  
Luigi Tesio
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Thermal Sensation ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
The Body ◽  
Post Stroke ◽  
Thalamic Stroke ◽  
Motor Cortex Excitability

Although rare, central post-stroke pain remains one of the most refractory forms of neuropathic pain. Repetitive transcranial magnetic stimulation (rTMS) has been reported to be effective in chronic cases. However, there are no data on the effects in the acute and subacute phases after stroke. In this study, we present a case of a patient with thalamic stroke with acute onset of pain and paresthesia who was responsive to rTMS. After a right thalamic stroke, a 32-year-old woman presented with drug-resistant pain and paresthesia on the left side of the body. There were no motor or sensory deficits, except for blunted thermal sensation and allodynia on light touch. Ten daily sessions were performed, where 10 Hz rTMS was applied to the hand area of the right primary motor cortex, 40 days after stroke. Before rTMS treatment (T0), immediately after treatment conclusion (T1), and 1 month after treatment (T2), three pain questionnaires were administered, and cortical responses to single and paired-pulse TMS were assessed. Eight healthy participants served as controls. At T0, when the patient was experiencing the worst pain, the excitability of the ipsilesional motor cortex was reduced. At T1 and T2, the pain scores and paresthesia' spread decreased. The clinical improvement was paralleled by the recovery in motor cortex excitability of the affected hemisphere, in terms of both intra- and inter-hemispheric connections. In this subacute central post-stroke pain case, rTMS treatment was associated with decreased pain and motor cortex excitability changes.

Abstract 2806: Does Motor Cortex Activity Predict Motor Recovery? An fMRI Study of Subacute Lacunar Stroke

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Assia Jaillard ◽  
Chantal Delon martin ◽  
Leeanne Carey ◽  
Laurent Lalamalle ◽  
Marc J Hommel ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Motor Recovery ◽  
Small Sample ◽  
Stroke Onset ◽  
Stroke Recovery ◽  
Finger Tapping ◽  
Lacunar Stroke ◽  
Related Activity ◽  
Recovery Score

Background: While primary motor cortex (M1) has been demonstrated to be crucial for motor recovery in a recent meta-analysis including fMRI and TMS studies, other functional neuroimaging studies have found that activity in a broader sensorimotor cortical network correlate with motor recovery. The heterogeneity of stroke lesions and the small sample size characterizing many studies could account for these discrepancies. Hypothesis : The strength of task-related activity in primary motor cortex predicts motor recovery in a clinically homogenous population of acute lacunar stroke patients. Methods: We used fMRI to investigate the neural mechanisms of stroke recovery. We studied 18 stroke patient (4 females, 14 males) after their first single lacunar stroke (7 right , 11 left hemisphere). The lesions caused pure hemiparesia one week after stroke onset (mean 7.2 days; range 2 -15). Lesions were limited to the deep territory of the anterior choroid artery, involving the corticospinal tract at the level of the internal capsule or the corona radiata ( Figure 1 ). Patients were matched to 18 healthy controls for age and sex. Motor impairment was assessed using the NIH Stroke Scale (NIHSS), the Fugl-Meyer Scale (FMS), Finger Tapping Score (FTS), Purdue Pegboard and simple reaction times 7 days and 6 months after stroke. At 6 months, a global motor recovery score was computed using the FMS and the FTS to assess motor recovery. Functional MRI scans were obtained using a self-paced finger tapping (FT) task implemented as a block design alternating right FT, left FT and rest. Data were processed using SPM8. In the first level analysis “FT minus fixation” contrasts were computed for the impaired hand. At the second level, multiple regression was used to assess the effect of the motor recovery score on the FT-related motor activity (threshold p<0.05 FWE; extent threshold k=5). Age and FT rate recorded during the experiment were included as covariates in the second level model. Results: As a group, the patients showed good recovery at 6 months. Both patients and controls exhibited a typical pattern of FT task-related activity. Activity in primary motor cortex predicted motor recovery at 6 months, after adjustment for age and FT rate. MNI coordinates = [-34,-14,48] See Figure 1 . Conclusions: Primary motor cortex activity, measured soon after stroke onset, predicts motor recovery assessed at 6 months post-stroke. fMRI measurements made in the early phase of stroke recovery could be useful to derive prognostic biomarkers in both clinical practice and clinical trials investigating novel treatments, such as stem cell administration.

Sign in / Sign up

Export Citation Format

Share Document